On 10/27/22 4:19 AM, Yang Yingliang wrote:
If device_register() returns error in rbd_sysfs_init(), name of kobject
which is allocated in dev_set_name() called in device_add() is leaked.
As comment of device_add() says, it should call put_device() to drop
the reference count that was set in device_initialize() when it fails,
so the name can be freed in kobject_cleanup().
Fault injection test can trigger this problem:
unreferenced object 0xffff88810173aa78 (size 8):
comm "modprobe", pid 247, jiffies 4294714278 (age 31.789s)
hex dump (first 8 bytes):
72 62 64 00 81 88 ff ff rbd.....
backtrace:
[<00000000f58fae56>] __kmalloc_node_track_caller+0x44/0x1b0
[<00000000bdd44fe7>] kstrdup+0x3a/0x70
[<00000000f7844d0b>] kstrdup_const+0x63/0x80
[<000000001b0a0eeb>] kvasprintf_const+0x10b/0x190
[<00000000a47bd894>] kobject_set_name_vargs+0x56/0x150
[<00000000d5edbf18>] dev_set_name+0xab/0xe0
[<00000000f5153e80>] device_add+0x106/0x1f20
Fixes: dfc5606dc513 ("rbd: replace the rbd sysfs interface")
Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
This looks right to me.
Reviewed-by: Alex Elder <elder@xxxxxxxxxx>
---
drivers/block/rbd.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index f9e39301c4af..04453f4a319c 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -7222,8 +7222,10 @@ static int __init rbd_sysfs_init(void)
int ret;
ret = device_register(&rbd_root_dev);
- if (ret < 0)
+ if (ret < 0) {
+ put_device(&rbd_root_dev);
return ret;
+ }
ret = bus_register(&rbd_bus_type);
if (ret < 0)
